Conrad Duenkel creating a new vase
in his Fair Haven studio

A brief history of glass:

The first evidence of man-made
glass is from Mesopotamia about
40 centuries ago. Cuneiform clay
tablets from that time contain secret,
highly-ritualized instructions for
furnace-building and glass-making.

The actual "blowing" of glass
was developed by Romans in Phoenicia
in the first century B.C.

Glass is made by melting quartz
sand, limestone and sodium carbonate
in a furnace heated to about 2500
degrees for as much as 24 hours.

Colors are added to glass by the
addition of metallic inorganic compounds
or bits of antique colored glass.

Melted glass has the consistency
of thick honey. It can be collected
on the end of a hollow tube and
then blown, shaped and cut by the
glass artist.

Once finished, the piece of art
glass is allowed to cool in a controlled
manner for several days to avoid
stress fractures from over-rapid
cooling.

Further information is available
at Wikipedia and the Corning Museum
of Glass: